Biaxially oriented polyester film and release film using the same

Abstract

A biaxially oriented polyester film which is facilitated in the detection of defects by optical inspection and minimizes the amount of oligomers deposited on a surface of the film. This film is useful for liquid crystal displays as well as a release film.

1 . A biaxially oriented polyester film comprising
 a polyester film having a main orientation axis which extends in a direction having an angle of not more than 11°, and a film haze value of 10 to 25%, and   a coating layer comprising a silane compound which is formed on at least one surface of the polyester film,   an amount of an oligomer deposited on a surface of the coating layer when heating the film at 180° C. for 5 min being not more than 3.0 mg/m 2 .   
     
     
         2 . A biaxially oriented polyester film according to  claim 1 , wherein the silane compound has an amino group. 
     
     
         3 . A release film which comprises the biaxially oriented polyester film as defined in  claim 1  and a release layer formed on the coating layer of the biaxially oriented polyester film, and which has a peel force of 10 to 100 mN/cm.